Bulletin 79-04: Incorrect Weights For Swing Check Valves Manufactured by Velan Engineering Corporation
UNITED STATES
NUCLEAR REGULATORY COMMISSION
OFFICE OF INSPECTION AND ENFORCEMENT
WASHINGTON, D.C. 20555
March 30, 1979
IE Bulletin No. 79-04
INCORRECT WEIGHTS FOR SWING CHECK VALVES MANUFACTURED BY VELAN ENGINEERING
CORPORATION
Description of Circumstances:
North Anna No. 1, Beaver Valley No. 1 and Salem No. 1 have reported to the
NRC that they had been provided incorrect weights for the six inch swing
check valves provided by Velan Engineering Corporation. The six inch valve
weight provided on the drawing was 225 pounds, whereas the actual weight has
been determined to be 450 pounds. In addition to the 6 inch valves,
drawings for 3 inch valves have specified 60 pounds weight while the
measured wight by the manufacturer was 85 pounds and drawings for 4 inch
valves have specified 100 pounds weight while the measured weight was 135
pounds. The manufacturer presently estimates the following maximum weights
for swing check valves.
Maximum Weight (lbs)
Nominal Valve Size for High Pressure (1500 psi)
Up to 1973 After 1973
3 inches 85 100
4 inches 135 150
6 inches 450 525
8 inches 750 1200
10 inches 1200 1200
The NRC staff has indications that in some case, incorrect valve weights
derived from engineering drawings were used in piping stress analyses. The
staff is not aware of a significant difference in the actual weight and the
weight provided on drawings for the 8 and 10 inch valves.
.
IE Bulletin No. 79 - 04 March 30, 1979
Page 2 of 3
It is recognized that there is a significant number of Velan swing check
valves used in nuclear systems and it is possible that other stress analyses
have been performed with incorrect valve weights.
Action To Be Taken By Licensees and Permit Holders:
1. List all Seismic Category I piping systems (or portions thereof) where
3, 4, or 6, inch diameter Velan swing check valves are installed or are
scheduled to be installed.
2. Verify for all those systems identified in item 1 above that correct
check valve weights were used in the piping analysis. Explain how and
when the correct valve weights were determined.
3. If incorrect valve weights were used, explain what actions have been
taken or are planned to re-evaluate the piping systems affected.
4. Specify for all the affected systems identified in Item 1 whether
modifications were or are required to the piping systems or their
supports because of changes in valve weight. Also, include the basis
for this determination. For those systems in which the actual valve
weight is greater than the design weight provide a summary of stresses
and loads and their allowable limits for the piping and its supports.
5. Identify the analytical technique including identification of any
computer codes used to determine the stresses indicated in Item 4.
6. All holders of operating licenses for power reactor facilities are
requested to complete Items 1 through 5 as promptly as possible, but no
later than May 1, 1979. Report in writing by May 1, 1979, to the
Director of the appropriate NRC Regional Office to describe your
evaluation, any discrepancies in meeting Items 1 through 5, and, if
necessary, your plans and schedule for resolution. For planned action,
a final report is to be submitted upon completion of your action.
.
IE Bulletin No. 79 -04 March 30, 1979
Page 3 of 3
A copy of your report(s) should be sent to the United States Nuclear
Regulatory Commission, Office of Inspection and Enforcement, Division
of Reactor Operations Inspection, Washington, D.C. 20555. These
reporting requirements do not preclude nor substitute for the
applicable requirements to report as set forth in the regulations and
license.
7. All holders of construction permits for power reactor facilities are
requested to describe your actions to assure that Items 1 through 5
will be satisfied before plant startup. Documentation of these actions
is to be maintained on site and available for NRC inspection. Report in
writing within (60) days of date of Bulletin issuance, to the Director
of the appropriate NRC Regional Office, completion of your review and
describe any discrepancies in meeting Items 1 through 5 and, if
necessary, your plans and schedule for resolution. A copy of your
report should be sent to the United States Nuclear Regulatory
Commission, Office of Inspection and Enforcement, Division of Reactor
Construction Inspection, Washington, D.C. 20555.
Approved by GAO B180225 (R0072): clearance expires 7/31/80. Approval was
given under a blanket clearance specifically for identified generic
problems.
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